Magnetostriction apparatus



May 12, 1953 E. J. cRoNlN MAGNETosTRIcTIoN APPARATUS Filed May 5, 1950:FIST-l INVENTOR.

A 7'7'0R/YE Y Patented May 12, 1953 MAGNETOSTRICTION APPARATUS Eugene J.Cronin, San Mateo, Calif.

Application May 5, 1950, Serial No. 160,224

(Cl. S18-118) 3 Claims.

My invention relates broadly to magnetostriction oscillator systems andmore particularly to a method of operation and construction ofmagnetostriction oscillator capable of operation over a relatively widefrequency range.

One of the objects of my invention is to provide a method of operating amagnetostriction oscillator in the ultra-sonic frequency range over arelatively wide range of frequencies.

Another object of my invention is to provide a method of assembling amultiplicity of magnetostrictive elements in a unit capable ofsustaining any one of the frequencies individual to the severalmagentostrictive elements and operative to develop pressure effectsincidental to the operation of the individual magnetostrictive elements.

Still another object of my invention is to provide a construction ofmagnetostriction device which may be connected in an electrical circuitand which is operative to sustain any one of a multiplicity offrequencies by the operation of a tuning circuit which is associatedwith the device.

Still another object of my invention is to provide a construction ofmagnetostriction device in which a multiplicity of wires each possessingdifferent rnagnetostrictive frequency characteristics are interralatedas la unit and electrically connected in a circuit operative to sustainany one of the individual frequencies characteristic of the multiplicityof magnetostrictive wires.

Still another object of my invention is to provide a construction ofmagnetostrictive device constituted by an assembly of spheres ofdiffering diameters each possessing individual magnetostrictivefrequency characteristics, the assembly being associated with anelectrical circuit tunable over a frequency range embracing thefrequencies of all of the magnetostrictive spheres whereby themagnetostrictive assembly may be utilized to sustain frequencies over larelatively wide frequency range.

Still another object of my invention is to provide an improved assemblyfor a multiplicity of magnetostrictive elements, each possessingdiffering frequency characteristics whereby any one of the individualfrequencies of the magnetostrictive elements may be sustained.

A still further object of my invention is to provide an assembly of amultiplicity of magnetostrictive elements capable of generating mag- 5'netostrictive Apressures over relatively wide frequency ranges of theorder of 60,000 cycles, and higher.

Other and further objects of my invention reside in novel technique inthe manufacture, production and utilization of multiplicity frequencymagnetostrictive units as set forth more fully in the specificationhereinafter following by reference to the accompanying drawings, inwhich:

Figure 1 is a schematic view showing the manner of initially assemblingthe magnetostrictive wires preparatory to the compacting of themagnetostrictive wires into the apparatus unit of my invention; Fig. 2is a plan view of the assembly of magnetostrictive wires shown in Fig. 1and illustrating the manner of assembling the wires which possessdiffering magnetostrictive frequency characteristics; Fig. 3 illustratesthe manner of carrying out the molding operation for compacting themagnetostrictive wires as a unit; Fig. 4 is a schematic circuitarrangement of an oscillator system associated with the magnetostrictionapparatus of my invention; Fig. 5 is a vertical sectional view takenthrough a modified form of my invention substantially on line 5--5 ofFig. 6 and illustrating the manner of yassembling a multiplicity ofspheres of differing magnetostrictive frequency characteristics in acompact unit; Fig. 6 is a horizontal sectional view through themagnetostriction 'apparatus illustrated in Fig. 5, the view being takensubstantially on line `t`6 thereof; Fig. 7 is a schematic view of themagnetostriction apparatus of Figs. 5 and 6, showing the manner offocussing the magnetostrictive pressures; Fig. 8 is a diagrammatic Viewshowing the manner in which an individual spherical magnetostrictiveelement operates to concentrate the magnetostrictive pressure in a beam;Fig. 9 illustrates the manner in which the magnetostrictive pressureeffects may be oriented and focussed with respect to a spherical form ofmagnetostrictive element; Fig. 10 schematically shows the manner ofassembling a multiple number of layers of spherical magnetostrictiveelements in a magnetostriction apparatus embodying my invention; andFig. 11 is a perspective View of one of the commercial forms of thedevices of my invention.

My invention is directed to the technique in the art of magnetostrictionwhereby a unit formed by a composite assembly of a multiplicity ofindividual magnetostrictive elements may be associated with anelectrical circuit responsive to the entire frequency range of themagnetostrictive elements for sustaining oscillations generated at lanyone of the frequencies incidental to selected magnetostrictive elementsin the composite assembly.

Heretofore in the art the application of magnetostriction techniques hasbeen limited by the i disadvantage that in order to change frequencyated in the same manner described for oil-well p drilling. One importantadvantage of this technique in mining is that it permits the mining of avein of ore without removing the surrounding native rock, and otherextraneous material, except when necessary to permit passage of thedrilling apparatus. This is possible because the materials possessingdifferent physical characteristics have therefore different frequencyresponses and will not be cavitated in the process. Thus the need forshothole drilling, blasting, mucking, hauling, and milling of tons ofvalueless earth is largely eliminated.

The drilling of tunnels normally necessitates the use of a special typeof mounting equipped with several drilling heads instead of only one.These heads are arranged on a framework so that they may be moved upagainst the formation to be tunneled as a unit. The procedure for theremoval of the cuttings is the same as hereinbefore set forth.

This technique of cavitation at extremely high pressures is applicableto phases of road building, especially resurfacing. .A tractor-type unithaving a series of batteries of resonators of the type set forth herein,suspended from a rear platform, proceeds over an old roadbed to beresurfaced, one battery of resonators tuned so that they cavitate theroadbed upon contact, While a second battery of resonators operate on adifferent frequency and are used to level and compress the pulverizedsurface back into position by the tremendous pressure developed. Athirdbattery of resonators on the same frame is connected to the tar orsurfacing material distribution system which causes the surface materialto be spread onto the road in an atomized condition at considerablepressure. These techniques allow a more complete pulverizing of theroadbed material and compression of the tar or other surf face than hasheretofore been attained. With such units it is possible to resurface aroad in one operation while driving over it at a slow speed.

Other industrial applications of magnetostrictive ultra-sonic energydevices embodying my invention and operating at selective frequencieswill readily suggest themselves, such as laundry and clothes washingequipment Where water is forced under pressure against the textiles tobe cleaned.

Referring to the drawings in more detail, reference character Idesignates a plate of insulation material arranged for the assembly ofthe devices of my invention during production. The magnetostrictiveWires shown at 2 are cut in relatively short lengths of the order of11/2 inches. lThe nickel wires are cut to predetermined lengthsaccording to the magnetostrictive frequency characteristics possessedthereby and are set into a mold of insulation material represented at 3.These wires are formed from nickel possessing magnetic properties andthey are caused to stand vertically erect on their ends as representedin Fig. 1 by polarization by the bar magnet Il located beneath the plateof insulation material. A plastic insulation material in the fiuid stateis poured into the mold 3 around the vertically erect nickel wires 2 andseeps around the wires 2 as represented at 5, and levels off at the topof the mold 3. The wires 2 may be promiscuously arranged Within the mold3 in generally spiral paths, as represented more particularly in Fig. 2.The pouring operation occurs while the wires 2 are maintained verticallyerect in the mold 3 by the polarization due to magnet Il.

The plastic is allowed to solidify forming the unit as represented inFig. 3 wherein the magnetostrictive Wires 2 have adjacent ends thereofcoplanar and their opposite ends of varying lengths terminating instaggered relation within the solidified plastic 5. Fig. 3 shows thecompleted magnetostrictive unit in inverted position. The opposite endsof the plastic unit extend in spaced planes substantially parallel toeach other. The plastic unit thus formed has a minor vertical axis and amajor horizontal axis. That is to say the horizontal axis predominates.

In Fig. 4 I have shown the mnner of utilizing the magnetostrictive unitin an oscillator circuit where the unit is encircled by an operatingwinding 6 which is electrically connected with an ultra-high frequencyelectron tube oscillator circuit, represented generally at l. Theultra-high frequency oscillator circuit includes electron tube 8 havingcathode 8a, control grid 8b and anode 8c. wherein the input and outputcircuits are coupled through the electrical winding 5 which encirclesthe magnetostriction unit of my invention. The oscillator circuit 8includes source of anode potential connected at terminals 9 throughradio frequency choke coil l 0 connected to anode 8c. The output circuitof the oscillator includes condenser Il connected between anode 8c andone end of the side of the electrical winding 6. The other end of theelectrical Winding 6 connects to grid electrode 8b and an intermediatetap H in electrical winding E connected to cathode 8a. The electricalWinding 6 and the oscillator circuit l are variably tuned by condenserI2 for adjusting the oscillator system selectively over the resonantrange of the several magnetostrictive frequencies possessed by themagnetostrictive wires 2. By adjusting condenser I2 the frequency of anyone of the magnetostrictive frequency characteristics of the severalmagnetostrictive elements 2 may be selectively sustained. It isunnecessary to remove a magnetostrictive element of one frequency andsubstitute a magnetostrictive element of a different frequency asheretofore required in the art.

The magnetostrictive unit as shown in Fig. 4 has the electrical winding6 thereof hermetically protected by the casing of insulation material M,the opposite ends of which are substantially coplanar with the planes ofthe opposite ends of the plastic unit 5 which embeds themagnetostrictive wires 2, and because of the fact that themagnetostrictive elements are mounted in plastic 5 these elements arealso thoroughly protected within the mold 3. The pressure operating orgenerating face of the magnetostriction unit is designated at l5.

In Fig. 5 I have illustrated a modified form of my invention in whichspheres iii of magnetostrictive material differing from each other indiameter and correspondingly in magnetostrictive characteristics arepromiscuously deposited in the mold 3 during the manufacturing processas hereinbefore described in connection with Fig. l, and the liquidplastic flowed around the spheres for embedding the spheres in theplastic. As the spheres become smaller the magnetostrictive frequencybecomes higher. The spheres might be made microscopic in size byatomizing molten metal into water or oil. The spheres of different sizesresonate at different magnetostrictive frequencies. Thus a multiplicityof magnetostrictive spheres consolidated into one large unit can embracea broad band of frequencies, any one of which can be selected when theapparatus is `connectedtin ansoscillator circuitv as shown in-flifig.

'resented fat w18, with ""a'rparabolicelike 41*. eflector back' I9 overArwhicl1:.=tl1e;magnetostrictive spheres 'Nierepromiscuousglyf.distributedvwithin the; plasticl 15."I'heg;pressure.eiects Egeneratedhy the; several. spheresaregeoncentrated upon 'afocalfpoint 2t :which 'is :located at the'center of Ian;'arc-icining two-eidesnfthe-encompassing-,coil 6. Thebalance of thezstructuref shown-lullig "7- is-sixnilar tothestri-ictures shown zifi-Figs. 5 and' V6.

vliligs. A8 :andi-9 are .'diagra-rnmatical yiews 4ex plaining .thegeneration.of-;n1agnetostrictivepressure effects 'hy'a magnetostrictivesphere, suchfas .16, and :the emanation-cf such vpressur-e -teiects InzFig. i8 the-electrical AilV i-r1dir 1g 6" is lillustrated surrounding'the :magnetos-trictive -sphere .l-G which serves: -asa convex--lensffor directing ymagnetostrictive--energy Aalong the; pathsdesignated atft and -2-5. Anothermovement :of the sphere 1G' to theposition shown in Fig. 9:'serves to shift the ',beam of energy emanating1fromthe -magiziletostrictive sphere |6'teftl'1ev directionsf24 and lInFig. l0 Ihave shown the manner-.orarrang-ing a multiplicityv of. layers`of -magnetostrictive :spheres in plastic for securing the'conjointaction thereof. l5-have:y illustrated one layer of l magnetostrictiyel*spheres yat 2|, @an .adjacent layer-fof magnetostrictitve spheres .at'22, and :a further --layer of -v -magnetostrictive f ,spheres at `23.The .several magnetestriotive:spheres may include spheres-ofdiife-ring-'di-ameters and ,correspondingly ,differentmagnetostr-ictivefrequency characteristics.

In Fig. 1 1 I: 4have .show-none of .thecommercial embodimentslcof myinvention'in the form of .a

circular disc having a thickness sucientf'to inv clude.' amultiplicityfof :em-bedded vmagnetostrictive L spheresfwhichfare vshownIat A vI 6 ,With Ominute portions ofthesphericalsurfaces thereofextending tangentiallyf-to;af-planertransverseto. the

endfof `,the L-magnetostrictive l unit.

yI Ahave found "-the -magnetostriction:apparatus i of -myainventionweryfeective-.and -eicient :in its operation, :and -While I 'have-describedcertain' of the embodimentsof i my invention Ifrealize thatmodifications 4may lbe made and I desire it'to :be be understood.that-no limitations'upon'my invention are intended otherthanmay:bef':imposed by thescope' of Vthe appended claims.

8 y-What I .claim as new var,1 cl- .rlesire to secure @by Letters`Patentof theUnited Statesisras follows: .1. Magnetostriction apparatus-scomprising 'a multiplicity of spheres -of .differing-diameters havingdiffering magnetostrictive frequency-characteristics, means formaintaining said-spheres in :compact relation, any electrical Winding2embracing all ofl said spheres, -an 4oscillator-circuit connected withsaid electrioa'l'fwinding, andl means for 'tuning' said oscillatorcircuit over .a lfrequeilcy range embracive of the `magnetostrietive.frequencies of all Vof said spheres ffor selectively sustaining themagnetostrictive'frequencynf any one of the magnetostrictive frequenciesof .said spheres generating Apressures incident there to, vthemagnetostrictive pressure effects :generated by said pheres. beingfocussed at a point disposed inthe center of anarcextendingloetween twosides of the .electrical vWinding embracing said spheres..

2. Magnetostriction apparatus :comprising 'a casing of insulationmaterial open atone :end and'terminating in a circularcurved Wallet utheoposite end, a multiplicity ofzspheres differing-in diameter anddiffering in magnetostrictive characteristics one -from anotherassembled against said curved wall, a plastic filling for said leasingsurrounding said spheres and maintaining the assembled position thereofand an electrical Winding surrounding said casing within themagnetostrictive fields .of said spheres.

. 3. Magnetostriction apparatus asset "forth in claim 2 in which saidcasing has A-a `cylindrical side Wall terminating' in a'flat -p1ane,saidplastic filling terminating in a 'ilat plane coincident with theaforesaid plane andsaid electrical'winding-being'iisposed around-thecylindrical side Wall of the casing with the focal point o'f thepressure eifects generated by thel several spheres lying outside the'flat plane of r'said plastic filling.

EUGENE J. CRONIN.

References Cited in the le of this patent UNITED STATES 4PATENTS NumberName Date 974,024 Carter Oct. 25,:1-.910 1,121,859 ,Messter Dec. 22,1914 `1,750,124 Pierce `Mar. 11, 1-930 2,116,522 Kunze May 10, 119382,328,496 Rocard Aug. 31, 1943 2,398,117 Rost et al Apr. 9, 19462,532,876 -Ashe Dec. A5, 1-950 FOREIGN PATENTS Number Country Date413,762 Great Britain July 26,` 1934

